Inhibition of the toxic byproduct during photocatalytic NO oxidation via La doping in ZnO

Abstract

It is of a great challenge to develop semiconductor photocatalysts with potential possibilities to simultaneously enhance photocatalytic efficiency and inhibit generation of toxic intermediates. In this study, we developed a facile method to induce the La doping and cationic vacancie (VZn) on ZnO for the highly efficient complete NO oxidation. The photocatalytic NO removal efficiency increases from 36.2% to 53.6%. Most importantly, a significant suppressed NO2 production also has been realized. According to the DFT calculations, ESR spectra and in situ FTIR spectra, the introduction of La3+ induce the redistribution of charge carriers in La-ZnO, which promote the production of O2− and lead to the formation of VZn for the formation of OH, contributing to the complete oxidation of NO to nitrate. Besides, the conversion pathway of photocatalytic NO oxidation has been elaborated. This work paves a new way to simultaneously realize the photocatalytic pollutants removal and the inhibition of toxic intermediates generation for efficient and safe air purification.